11219Skas # 21219Skas 31219Skas #include "rcv.h" 41219Skas #include <sys/stat.h> 51219Skas #include <ctype.h> 61219Skas 71219Skas /* 81219Skas * Mail -- a mail program 91219Skas * 101219Skas * Auxiliary functions. 111219Skas */ 121219Skas 13*5237Skurt static char *SccsId = "@(#)aux.c 2.3 12/10/81"; 141219Skas 151219Skas /* 161219Skas * Return a pointer to a dynamic copy of the argument. 171219Skas */ 181219Skas 191219Skas char * 201219Skas savestr(str) 211219Skas char *str; 221219Skas { 231219Skas register char *cp, *cp2, *top; 241219Skas 251219Skas for (cp = str; *cp; cp++) 261219Skas ; 271219Skas top = salloc(cp-str + 1); 281219Skas if (top == NOSTR) 291219Skas return(NOSTR); 301219Skas for (cp = str, cp2 = top; *cp; cp++) 311219Skas *cp2++ = *cp; 321219Skas *cp2 = 0; 331219Skas return(top); 341219Skas } 351219Skas 361219Skas /* 371219Skas * Copy the name from the passed header line into the passed 381219Skas * name buffer. Null pad the name buffer. 391219Skas */ 401219Skas 411219Skas copyname(linebuf, nbuf) 421219Skas char *linebuf, *nbuf; 431219Skas { 441219Skas register char *cp, *cp2; 451219Skas 461219Skas for (cp = linebuf + 5, cp2 = nbuf; *cp != ' ' && cp2-nbuf < 8; cp++) 471219Skas *cp2++ = *cp; 481219Skas while (cp2-nbuf < 8) 491219Skas *cp2++ = 0; 501219Skas } 511219Skas 521219Skas /* 531219Skas * Announce a fatal error and die. 541219Skas */ 551219Skas 561219Skas panic(str) 571219Skas char *str; 581219Skas { 591219Skas prs("panic: "); 601219Skas prs(str); 611219Skas prs("\n"); 621219Skas exit(1); 631219Skas } 641219Skas 651219Skas /* 661219Skas * Catch stdio errors and report them more nicely. 671219Skas */ 681219Skas 691219Skas _error(str) 701219Skas char *str; 711219Skas { 721219Skas prs("Stdio Error: "); 731219Skas prs(str); 741219Skas prs("\n"); 751219Skas abort(); 761219Skas } 771219Skas 781219Skas /* 791219Skas * Print a string on diagnostic output. 801219Skas */ 811219Skas 821219Skas prs(str) 831219Skas char *str; 841219Skas { 851219Skas register char *s; 861219Skas 871219Skas for (s = str; *s; s++) 881219Skas ; 891219Skas write(2, str, s-str); 901219Skas } 911219Skas 921219Skas /* 931219Skas * Touch the named message by setting its MTOUCH flag. 941219Skas * Touched messages have the effect of not being sent 951219Skas * back to the system mailbox on exit. 961219Skas */ 971219Skas 981219Skas touch(mesg) 991219Skas { 1001479Skas register struct message *mp; 1011479Skas 1021479Skas if (mesg < 1 || mesg > msgCount) 1031479Skas return; 1041479Skas mp = &message[mesg-1]; 1051479Skas mp->m_flag |= MTOUCH; 1061479Skas if ((mp->m_flag & MREAD) == 0) 1071479Skas mp->m_flag |= MREAD|MSTATUS; 1081219Skas } 1091219Skas 1101219Skas /* 1111219Skas * Test to see if the passed file name is a directory. 1121219Skas * Return true if it is. 1131219Skas */ 1141219Skas 1151219Skas isdir(name) 1161219Skas char name[]; 1171219Skas { 1181219Skas struct stat sbuf; 1191219Skas 1201219Skas if (stat(name, &sbuf) < 0) 1211219Skas return(0); 1221219Skas return((sbuf.st_mode & S_IFMT) == S_IFDIR); 1231219Skas } 1241219Skas 1251219Skas /* 1261219Skas * Compute the size in characters of the passed message 1271219Skas */ 1281219Skas 1291219Skas unsigned int 1301219Skas msize(messp) 1311219Skas struct message *messp; 1321219Skas { 1331219Skas register struct message *mp; 1341219Skas 1351219Skas mp = messp; 1361219Skas return(mp->m_size); 1371219Skas } 1381219Skas 1391219Skas /* 1401219Skas * Count the number of arguments in the given string raw list. 1411219Skas */ 1421219Skas 1431219Skas argcount(argv) 1441219Skas char **argv; 1451219Skas { 1461219Skas register char **ap; 1471219Skas 1481219Skas for (ap = argv; *ap != NOSTR; ap++) 1491219Skas ; 1501219Skas return(ap-argv); 1511219Skas } 1521219Skas 1531219Skas /* 1541219Skas * Given a file address, determine the 1551219Skas * block number it represents. 1561219Skas */ 1571219Skas 1581219Skas blockof(off) 1591219Skas off_t off; 1601219Skas { 1611219Skas off_t a; 1621219Skas 1631219Skas a = off >> 9; 1641219Skas a &= 077777; 1651219Skas return((int) a); 1661219Skas } 1671219Skas 1681219Skas /* 1691219Skas * Take a file address, and determine 1701219Skas * its offset in the current block. 1711219Skas */ 1721219Skas 1731219Skas offsetof(off) 1741219Skas off_t off; 1751219Skas { 1761219Skas off_t a; 1771219Skas 1781219Skas a = off & 0777; 1791219Skas return((int) a); 1801219Skas } 1811219Skas 1821219Skas /* 1831219Skas * Determine if the passed file is actually a tty, via a call to 1841219Skas * gtty. This is not totally reliable, but . . . 1851219Skas */ 1861219Skas 1871219Skas isatty(f) 1881219Skas { 1891219Skas struct sgttyb buf; 1901219Skas 1911219Skas if (gtty(f, &buf) < 0) 1921219Skas return(0); 1931219Skas return(1); 1941219Skas } 1951219Skas 1961219Skas /* 1971219Skas * Return the desired header line from the passed message 1981219Skas * pointer (or NOSTR if the desired header field is not available). 1991219Skas */ 2001219Skas 2011219Skas char * 2021219Skas hfield(field, mp) 2031219Skas char field[]; 2041219Skas struct message *mp; 2051219Skas { 2061219Skas register FILE *ibuf; 2071219Skas char linebuf[LINESIZE]; 2081219Skas register int lc; 2091219Skas 2101219Skas ibuf = setinput(mp); 2111219Skas if ((lc = mp->m_lines) <= 0) 2121219Skas return(NOSTR); 2131219Skas if (readline(ibuf, linebuf) < 0) 2141219Skas return(NOSTR); 2151219Skas lc--; 2161219Skas do { 2171219Skas lc = gethfield(ibuf, linebuf, lc); 2181219Skas if (lc == -1) 2191219Skas return(NOSTR); 2201219Skas if (ishfield(linebuf, field)) 2211219Skas return(savestr(hcontents(linebuf))); 2221219Skas } while (lc > 0); 2231219Skas return(NOSTR); 2241219Skas } 2251219Skas 2261219Skas /* 2271219Skas * Return the next header field found in the given message. 2281219Skas * Return > 0 if something found, <= 0 elsewise. 2291219Skas * Must deal with \ continuations & other such fraud. 2301219Skas */ 2311219Skas 2321219Skas gethfield(f, linebuf, rem) 2331219Skas register FILE *f; 2341219Skas char linebuf[]; 2351219Skas register int rem; 2361219Skas { 2371219Skas char line2[LINESIZE]; 2381219Skas long loc; 2391219Skas register char *cp, *cp2; 2401219Skas register int c; 2411219Skas 2421219Skas 2431219Skas for (;;) { 2441219Skas if (rem <= 0) 2451219Skas return(-1); 2461219Skas if (readline(f, linebuf) < 0) 2471219Skas return(-1); 2481219Skas rem--; 2491219Skas if (strlen(linebuf) == 0) 2501219Skas return(-1); 2511219Skas if (isspace(linebuf[0])) 2521219Skas continue; 2531219Skas if (linebuf[0] == '>') 2541219Skas continue; 2551219Skas cp = index(linebuf, ':'); 2561219Skas if (cp == NOSTR) 2571219Skas continue; 2581219Skas for (cp2 = linebuf; cp2 < cp; cp2++) 2591219Skas if (isdigit(*cp2)) 2601219Skas continue; 2611219Skas 2621219Skas /* 2631219Skas * I guess we got a headline. 2641219Skas * Handle wraparounding 2651219Skas */ 2661219Skas 2671219Skas for (;;) { 2681219Skas if (rem <= 0) 2691219Skas break; 2701219Skas #ifdef CANTELL 2711219Skas loc = ftell(f); 2721219Skas if (readline(f, line2) < 0) 2731219Skas break; 2741219Skas rem--; 2751219Skas if (!isspace(line2[0])) { 2761219Skas fseek(f, loc, 0); 2771219Skas rem++; 2781219Skas break; 2791219Skas } 2801219Skas #else 2811219Skas c = getc(f); 2821219Skas ungetc(c, f); 2831219Skas if (!isspace(c) || c == '\n') 2841219Skas break; 2851219Skas if (readline(f, line2) < 0) 2861219Skas break; 2871219Skas rem--; 2881219Skas #endif 2891219Skas cp2 = line2; 2901219Skas for (cp2 = line2; *cp2 != 0 && isspace(*cp2); cp2++) 2911219Skas ; 2921219Skas if (strlen(linebuf) + strlen(cp2) >= LINESIZE-2) 2931219Skas break; 2941219Skas cp = &linebuf[strlen(linebuf)]; 2951219Skas while (cp > linebuf && 2961219Skas (isspace(cp[-1]) || cp[-1] == '\\')) 2971219Skas cp--; 2981219Skas *cp++ = ' '; 2991219Skas for (cp2 = line2; *cp2 != 0 && isspace(*cp2); cp2++) 3001219Skas ; 3011219Skas strcpy(cp, cp2); 3021219Skas } 3031219Skas if ((c = strlen(linebuf)) > 0) { 3041219Skas cp = &linebuf[c-1]; 3051219Skas while (cp > linebuf && isspace(*cp)) 3061219Skas cp--; 3071219Skas *++cp = 0; 3081219Skas } 3091219Skas return(rem); 3101219Skas } 3111219Skas /* NOTREACHED */ 3121219Skas } 3131219Skas 3141219Skas /* 3151219Skas * Check whether the passed line is a header line of 3161219Skas * the desired breed. 3171219Skas */ 3181219Skas 3191219Skas ishfield(linebuf, field) 3201219Skas char linebuf[], field[]; 3211219Skas { 3221219Skas register char *cp; 3231219Skas register int c; 3241219Skas 3251219Skas if ((cp = index(linebuf, ':')) == NOSTR) 3261219Skas return(0); 3271219Skas if (cp == linebuf) 3281219Skas return(0); 3291219Skas cp--; 3301219Skas while (cp > linebuf && isspace(*cp)) 3311219Skas cp--; 3321219Skas c = *++cp; 3331219Skas *cp = 0; 3341219Skas if (icequal(linebuf ,field)) { 3351219Skas *cp = c; 3361219Skas return(1); 3371219Skas } 3381219Skas *cp = c; 3391219Skas return(0); 3401219Skas } 3411219Skas 3421219Skas /* 3431219Skas * Extract the non label information from the given header field 3441219Skas * and return it. 3451219Skas */ 3461219Skas 3471219Skas char * 3481219Skas hcontents(hfield) 3491219Skas char hfield[]; 3501219Skas { 3511219Skas register char *cp; 3521219Skas 3531219Skas if ((cp = index(hfield, ':')) == NOSTR) 3541219Skas return(NOSTR); 3551219Skas cp++; 3561219Skas while (*cp && isspace(*cp)) 3571219Skas cp++; 3581219Skas return(cp); 3591219Skas } 3601219Skas 3611219Skas /* 3621219Skas * Compare two strings, ignoring case. 3631219Skas */ 3641219Skas 3651219Skas icequal(s1, s2) 3661219Skas register char *s1, *s2; 3671219Skas { 3681219Skas 3691219Skas while (raise(*s1++) == raise(*s2)) 3701219Skas if (*s2++ == 0) 3711219Skas return(1); 3721219Skas return(0); 3731219Skas } 3741219Skas 3751219Skas /* 3761219Skas * The following code deals with input stacking to do source 3771219Skas * commands. All but the current file pointer are saved on 3781219Skas * the stack. 3791219Skas */ 3801219Skas 3811219Skas static int ssp = -1; /* Top of file stack */ 3821519Skas struct sstack { 3831519Skas FILE *s_file; /* File we were in. */ 3841519Skas int s_cond; /* Saved state of conditionals */ 3851519Skas } sstack[_NFILE]; 3861219Skas 3871219Skas /* 3881219Skas * Pushdown current input file and switch to a new one. 3891219Skas * Set the global flag "sourcing" so that others will realize 3901219Skas * that they are no longer reading from a tty (in all probability). 3911219Skas */ 3921219Skas 3931219Skas source(name) 3941219Skas char name[]; 3951219Skas { 3961219Skas register FILE *fi; 3973914Skurt register char *cp; 3981219Skas 3993914Skurt if ((cp = expand(name)) == NOSTR) 4001219Skas return(1); 4013914Skurt if ((fi = fopen(cp, "r")) == NULL) { 4023914Skurt perror(cp); 4033914Skurt return(1); 4041219Skas } 4051219Skas if (ssp >= _NFILE-2) { 4061219Skas printf("Too much \"sourcing\" going on.\n"); 4071219Skas fclose(fi); 4081219Skas return(1); 4091219Skas } 4101519Skas sstack[++ssp].s_file = input; 4111519Skas sstack[ssp].s_cond = cond; 4121519Skas cond = CANY; 4131219Skas input = fi; 4141219Skas sourcing++; 4151219Skas return(0); 4161219Skas } 4171219Skas 4181219Skas /* 4191219Skas * Source a file, but do nothing if the file cannot be opened. 4201219Skas */ 4211219Skas 4221219Skas source1(name) 4231219Skas char name[]; 4241219Skas { 4251219Skas register int f; 4261219Skas 4271219Skas if ((f = open(name, 0)) < 0) 4281219Skas return(0); 4291219Skas close(f); 4301219Skas source(name); 4311219Skas } 4321219Skas 4331219Skas /* 4341219Skas * Pop the current input back to the previous level. 4351219Skas * Update the "sourcing" flag as appropriate. 4361219Skas */ 4371219Skas 4381219Skas unstack() 4391219Skas { 4401219Skas if (ssp < 0) { 4411219Skas printf("\"Source\" stack over-pop.\n"); 4421219Skas sourcing = 0; 4431219Skas return(1); 4441219Skas } 4451219Skas fclose(input); 4461519Skas if (cond != CANY) 4471519Skas printf("Unmatched \"if\"\n"); 4481519Skas cond = sstack[ssp].s_cond; 4491519Skas input = sstack[ssp--].s_file; 4501219Skas if (ssp < 0) 4511219Skas sourcing = 0; 4521219Skas return(0); 4531219Skas } 4541219Skas 4551219Skas /* 4561219Skas * Touch the indicated file. 4571219Skas * This is nifty for the shell. 4581219Skas * If we have the utime() system call, this is better served 4591219Skas * by using that, since it will work for empty files. 4601219Skas * On non-utime systems, we must sleep a second, then read. 4611219Skas */ 4621219Skas 4631219Skas alter(name) 4641219Skas char name[]; 4651219Skas { 4661219Skas #ifdef UTIME 4671219Skas struct stat statb; 4681219Skas long time(); 4691219Skas time_t time_p[2]; 4701219Skas #else 4711219Skas register int pid, f; 4721219Skas char w; 4731219Skas #endif UTIME 4741219Skas 4751219Skas #ifdef UTIME 4761219Skas if (stat(name, &statb) < 0) 4771219Skas return; 4781219Skas time_p[0] = time((long *) 0) + 1; 4791219Skas time_p[1] = statb.st_mtime; 4801219Skas utime(name, time_p); 4811219Skas #else 4821219Skas sleep(1); 4831219Skas if ((f = open(name, 0)) < 0) 4844389Skurt return; 4851219Skas read(f, &w, 1); 4861219Skas exit(0); 4871219Skas #endif 4881219Skas } 4891219Skas 4901219Skas /* 4911219Skas * Examine the passed line buffer and 4921219Skas * return true if it is all blanks and tabs. 4931219Skas */ 4941219Skas 4951219Skas blankline(linebuf) 4961219Skas char linebuf[]; 4971219Skas { 4981219Skas register char *cp; 4991219Skas 5001219Skas for (cp = linebuf; *cp; cp++) 5011219Skas if (!any(*cp, " \t")) 5021219Skas return(0); 5031219Skas return(1); 5041219Skas } 5051219Skas 5061219Skas /* 5073195Skas * Get sender's name from this message. If the message has 5083195Skas * a bunch of arpanet stuff in it, we may have to skin the name 5093195Skas * before returning it. 5103195Skas */ 5113195Skas char * 5123195Skas nameof(mp, reptype) 5133195Skas register struct message *mp; 5143195Skas { 515*5237Skurt register char *cp, *cp2; 5163195Skas 517*5237Skurt cp = skin(name1(mp, reptype)); 518*5237Skurt if (reptype != 0 || charcount(cp, '!') < 2) 519*5237Skurt return(cp); 520*5237Skurt cp2 = rindex(cp, '!'); 521*5237Skurt cp2--; 522*5237Skurt while (cp2 > cp && *cp2 != '!') 523*5237Skurt cp2--; 524*5237Skurt if (*cp2 == '!') 525*5237Skurt return(cp2 + 1); 526*5237Skurt return(cp); 5273195Skas } 5283195Skas 5293195Skas /* 5303195Skas * Skin an arpa net address according to the RFC 733 interpretation 5313195Skas * of "host-phrase." 5323195Skas */ 5333195Skas char * 5343195Skas skin(name) 5353195Skas char *name; 5363195Skas { 5373195Skas register int c; 5383195Skas register char *cp, *cp2; 5393195Skas int gotlt, lastsp; 5403195Skas char nbuf[BUFSIZ]; 5413195Skas 5423195Skas if (name == NOSTR) 5433195Skas return(NOSTR); 5443195Skas if (index(name, '(') == NOSTR && index(name, '<') == NOSTR) 5453195Skas return(name); 5463195Skas gotlt = 0; 5473195Skas lastsp = 0; 5483195Skas for (cp = name, cp2 = nbuf, c = *cp++; *cp; c = *cp++) { 5493195Skas switch (c) { 5503195Skas case '(': 5513195Skas while (*cp != ')' && *cp != 0) 5523195Skas cp++; 5533195Skas if (*cp) 5543195Skas cp++; 5553195Skas break; 5563195Skas 5573195Skas case ' ': 5583195Skas lastsp = 1; 5593195Skas break; 5603195Skas 5613195Skas case '<': 5623195Skas cp2 = nbuf; 5633195Skas gotlt++; 5643195Skas lastsp = 0; 5653195Skas break; 5663195Skas 5673195Skas case '>': 5683195Skas if (gotlt) 5693195Skas goto done; 5703195Skas 5713195Skas /* Fall into . . . */ 5723195Skas 5733195Skas default: 5743195Skas if (lastsp) { 5753195Skas lastsp = 0; 5763195Skas *cp2++ = ' '; 5773195Skas } 5783195Skas *cp2++ = c; 5793195Skas break; 5803195Skas } 5813195Skas } 5823195Skas done: 5833195Skas *cp2 = 0; 5843195Skas 5853195Skas return(savestr(nbuf)); 5863195Skas } 5873195Skas 5883195Skas /* 5891219Skas * Fetch the sender's name from the passed message. 5903195Skas * Reptype can be 5913195Skas * 0 -- get sender's name for display purposes 5923195Skas * 1 -- get sender's name for reply 5933195Skas * 2 -- get sender's name for Reply 5941219Skas */ 5951219Skas 5961219Skas char * 5973195Skas name1(mp, reptype) 5981219Skas register struct message *mp; 5991219Skas { 6001219Skas char namebuf[LINESIZE]; 6011219Skas char linebuf[LINESIZE]; 6021219Skas register char *cp, *cp2; 6031219Skas register FILE *ibuf; 6041219Skas int first = 1; 6051219Skas 6063195Skas #ifndef DELIVERMAIL 6073195Skas if ((cp = hfield("from", mp)) != NOSTR) 6083195Skas return(cp); 6093195Skas if (reptype == 0 && (cp = hfield("sender", mp)) != NOSTR) 6103195Skas return(cp); 6113195Skas #endif 6121219Skas ibuf = setinput(mp); 6131219Skas copy("", namebuf); 6141219Skas if (readline(ibuf, linebuf) <= 0) 6151219Skas return(savestr(namebuf)); 6161219Skas newname: 6171219Skas for (cp = linebuf; *cp != ' '; cp++) 6181219Skas ; 6191219Skas while (any(*cp, " \t")) 6201219Skas cp++; 6211219Skas for (cp2 = &namebuf[strlen(namebuf)]; *cp && !any(*cp, " \t") && 6221219Skas cp2-namebuf < LINESIZE-1; *cp2++ = *cp++) 6231219Skas ; 6241219Skas *cp2 = '\0'; 6251219Skas if (readline(ibuf, linebuf) <= 0) 6261219Skas return(savestr(namebuf)); 6271219Skas if ((cp = index(linebuf, 'F')) == NULL) 6281219Skas return(savestr(namebuf)); 6291219Skas if (strncmp(cp, "From", 4) != 0) 6301219Skas return(savestr(namebuf)); 6311219Skas while ((cp = index(cp, 'r')) != NULL) { 6321219Skas if (strncmp(cp, "remote", 6) == 0) { 6331219Skas if ((cp = index(cp, 'f')) == NULL) 6341219Skas break; 6351219Skas if (strncmp(cp, "from", 4) != 0) 6361219Skas break; 6371219Skas if ((cp = index(cp, ' ')) == NULL) 6381219Skas break; 6391219Skas cp++; 6401219Skas if (first) { 6411219Skas copy(cp, namebuf); 6421219Skas first = 0; 6431219Skas } else 6441219Skas strcpy(rindex(namebuf, '!')+1, cp); 6451219Skas strcat(namebuf, "!"); 6461219Skas goto newname; 6471219Skas } 6481219Skas cp++; 6491219Skas } 6501219Skas return(savestr(namebuf)); 6511219Skas } 6521219Skas 6531219Skas /* 654*5237Skurt * Count the occurances of c in str 655*5237Skurt */ 656*5237Skurt charcount(str, c) 657*5237Skurt char *str; 658*5237Skurt { 659*5237Skurt register char *cp; 660*5237Skurt register int i; 661*5237Skurt 662*5237Skurt for (i = 0, cp = str; *cp; cp++) 663*5237Skurt if (*cp == c) 664*5237Skurt i++; 665*5237Skurt return(i); 666*5237Skurt } 667*5237Skurt 668*5237Skurt /* 6691219Skas * Find the rightmost pointer to an instance of the 6701219Skas * character in the string and return it. 6711219Skas */ 6721219Skas char * 6731219Skas rindex(str, c) 6741219Skas char str[]; 6751219Skas register int c; 6761219Skas { 6771219Skas register char *cp, *cp2; 6781219Skas 6791219Skas for (cp = str, cp2 = NOSTR; *cp; cp++) 6801219Skas if (c == *cp) 6811219Skas cp2 = cp; 6821219Skas return(cp2); 6831219Skas } 6841219Skas 6851219Skas /* 6861219Skas * See if the string is a number. 6871219Skas */ 6881219Skas 6891219Skas numeric(str) 6901219Skas char str[]; 6911219Skas { 6921219Skas register char *cp = str; 6931219Skas 6941219Skas while (*cp) 6951219Skas if (!isdigit(*cp++)) 6961219Skas return(0); 6971219Skas return(1); 6981219Skas } 6991219Skas 7001219Skas /* 7011219Skas * Are any of the characters in the two strings the same? 7021219Skas */ 7031219Skas 7041219Skas anyof(s1, s2) 7051219Skas register char *s1, *s2; 7061219Skas { 7071219Skas register int c; 7081219Skas 7091219Skas while (c = *s1++) 7101219Skas if (any(c, s2)) 7111219Skas return(1); 7121219Skas return(0); 7131219Skas } 7141219Skas 7151219Skas /* 7161219Skas * Determine the leftmost index of the character 7171219Skas * in the string. 7181219Skas */ 7191219Skas 7201219Skas char * 7211219Skas index(str, ch) 7221219Skas char *str; 7231219Skas { 7241219Skas register char *cp; 7251219Skas register int c; 7261219Skas 7271219Skas for (c = ch, cp = str; *cp; cp++) 7281219Skas if (*cp == c) 7291219Skas return(cp); 7301219Skas return(NOSTR); 7311219Skas } 7321219Skas 7331219Skas /* 7341219Skas * String compare two strings of bounded length. 7351219Skas */ 7361219Skas 7371219Skas strncmp(as1, as2, an) 7381219Skas char *as1, *as2; 7391219Skas { 7401219Skas register char *s1, *s2; 7411219Skas register int n; 7421219Skas 7431219Skas s1 = as1; 7441219Skas s2 = as2; 7451219Skas n = an; 7461219Skas while (--n >= 0 && *s1 == *s2++) 7471219Skas if (*s1++ == '\0') 7481219Skas return(0); 7491219Skas return(n<0 ? 0 : *s1 - *--s2); 7501219Skas } 7511219Skas 752